secP256k1 not supported on OSX

[ixje]

Describe the bug
The single transaction in testnet block 49672 fails with a FAULT state when running neo-cli RC3 on OSX. The same transaction exits with a HALT state on Windows and Linux. This is due to using the system ECDSA (which was changed to here #2340) which does not support koblitz curves according to Microsoft where I tried to report the issue.

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
 ---> Interop+AppleCrypto+AppleCommonCryptoCryptographicException: Unknown format in import.
   at Interop.AppleCrypto.ImportEphemeralKey(ReadOnlySpan`1 keyBlob, Boolean hasPrivateKey)
   at System.Security.Cryptography.EccSecurityTransforms.ImportKey(ECParameters parameters)
   at System.Security.Cryptography.EccSecurityTransforms.ImportParameters(ECParameters parameters)
   at System.Security.Cryptography.ECDsa.ECDsaImplementation.ECDsaSecurityTransforms.ImportParameters(ECParameters parameters)
   at System.Security.Cryptography.ECDsa.Create(ECParameters parameters)
   at Neo.Cryptography.Crypto.VerifySignature(ReadOnlySpan`1 message, ReadOnlySpan`1 signature, ECPoint pubkey) in /Users/erik/Documents/code/neo3-csharp-rc3/neo/src/neo/Cryptography/Crypto.cs:line 67
   at Neo.Cryptography.Crypto.VerifySignature(ReadOnlySpan`1 message, ReadOnlySpan`1 signature, ReadOnlySpan`1 pubkey, ECCurve curve) in /Users/erik/Documents/code/neo3-csharp-rc3/neo/src/neo/Cryptography/Crypto.cs:line 89
   at Neo.SmartContract.Native.CryptoLib.VerifyWithECDsa(Byte[] message, Byte[] pubkey, Byte[] signature, NamedCurve curve) in /Users/erik/Documents/code/neo3-csharp-rc3/neo/src/neo/SmartContract/Native/CryptoLib.cs:line 56
   --- End of inner exception stack trace ---
   at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor, Boolean wrapExceptions)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.Reflection.MethodBase.Invoke(Object obj, Object[] parameters)
   at Neo.SmartContract.Native.NativeContract.Invoke(ApplicationEngine engine, Byte version) in /Users/erik/Documents/code/neo3-csharp-rc3/neo/src/neo/SmartContract/Native/NativeContract.cs:line 196

To Reproduce
The following code creates the same data as the above mentioned transaction would at this failing piece of NEO code

using System;
using System.Security.Cryptography;

namespace whatevertesting
{
    class Program
    {
        static void Main(string[] args)
        {
            byte[] message =
            {
                170,145,162,23,52,214,229,130,21,187,48,134,182,18,13,242,142,11,155,115,254,228,105,60,202,226,75,161,198,208,52,236
            };
            byte[] signature =
            {
                39, 234, 133, 46, 9, 81, 126, 32, 215, 159, 63, 99, 22, 126, 81, 132, 148, 122, 75, 194, 112, 52, 99,
                14, 148, 79, 92, 137, 250, 214, 124, 73, 42, 145, 46, 100, 154, 178, 86, 73, 69, 162, 121, 61, 127, 89,
                224, 215, 205, 30, 54, 100, 116, 230, 180, 143, 239, 45, 99, 83, 220, 83, 141, 90
            };
            byte[]
                buffer =
                {
                    4,
                    239, 68, 190, 186, 132, 66, 43, 215, 106, 89, 149, 49, 201, 254, 80, 150, 154, 146, 154, 15, 238,
                    53, 223, 102, 105, 15, 55, 12, 225, 159, 168, 192, 14, 212, 182, 73, 105, 29, 17, 107, 125, 238,
                    183, 155, 113, 65, 86, 209, 137, 129, 145, 110, 88, 174, 64, 192, 235, 172, 191, 59, 208, 184, 120,
                    119
                };

            using var ecdsa = ECDsa.Create(new ECParameters
            {
                Curve = ECCurve.CreateFromFriendlyName("secP256k1"),
                Q = new ECPoint
                {
                    X = buffer[1..33],
                    Y = buffer[33..]
                }
            });
            bool valid = ecdsa.VerifyData(message, signature, HashAlgorithmName.SHA256);
            Console.WriteLine(valid);
        }
    }
}

Expected behavior
I expect neo-cli to produces identical results on OSX as it would on Linux and Windows.

Platform:

• OS: OSX catalina
• Version: neo-cli rc3

[shargon]

It could be solved with a compiler directive, but I have no OSX for testing it, I will try to do it in the next days

[ixje]

@shargon I can test your solution